Reproducer for phonographs



H. M. DUNCAN.

HEPRODUCER FOR PHONOGRAPHS. APPLICATION FILED FEB. 3. 1921.

,1,41 1,565. Patente@ Apr. 4, 1922.

.yr/6j. 2

l INVENTOR.

j ATT HARRY M. DUN CAN 0F LOS ANGELES, CALIFORNIA.

REPROBUCER FOR vPHQNOGrJAlEI-IS.

Specification 0f Letters Patent.

Patented Apr. et, 1922.

Application filed February 3, `1921. Serial No. 442,184.

To all whom t may concern:

Be it known that l, HARRY il. DUNCAN, a citizen ot the United States, residing at Los Angeles, in the county orf Los Angeles and State oi California, have invented new and uset'ul improvements in leproducers tor lhonographs, ot which the following is a specification.

lt is the object ot this invention to provide a sound'reproducer having extremely simple but eiiicient means tor varying the intensity ot the sound produced.

A reproducer constructed in accordance with the invention will also eliminate to a great extent all scratching sounds incident to the employment ot usual reproducers. Variations in the intensity ot the sound and the elimination ot scratching is produced by providing a spring loop in the stylus bar and mounting a clamping member upon said spring loop for adjustment upon the same.

The invention will be readily understood trom the following` description ot the accompanying drawings, in which Figure 1 is a front elevation ot' a reproducer constructed in accordance with the invention.

Fig. 2 is a section through the same on the line 2 2 ot' Fig. 1.

Fig. 3 is a detail section on the line 3-3 of Fig. l.

The reproducer in its general construction may be ot standard design and is illustrated as including a casing '1 carrying a diaphragm 2 mounted between annular sup porting rings A. usual sound opening L1- projects trom the casing and is provided with a usual connection 5 by means ot which the reproducer is mounted upon a tone arm. The stylus bar 6 extends radially of diaphragm 2 in usual manner and is mounted upon a lug projecting beyond casing 1 so that the stylus bar may be rocked slightly to move the end of' the same overlying the diaphragm toward and away tromthe diaphragm. The projecting end of the stylus bar is provided with a usual. socket S adapted to receive a stylus 9 held in position by means ot set screw 10.

In my improved reproducer the end ot the stylus bar which overlies the diaphragm 2, instead of being directly secured thereto at the center ot the diaphragm, is provided with a spring loop 12 projecting longitudinally beyond the stylus bar an appreciable distance beyond the center of the diaphragm and then being reversely bent, as shown at 12, with the end of said reversely bent portion secured to the center of the diaphragm, as shown at 13.

A clamping member is mounted upon the spring loop thus formed and is shown as comprising a casing 14 having the two arms o the loop received through the same with a block 15 interposed between the loop arms and movably secured within casing 14 by means ot a pin 1G extending through the block and having its ends received in longitudinal slots 17 provided in casing 14. A set screw `18 is threaded through casing 1st and is adapted to impinge against one ot the Y loop arms for clamping the loop arms to block 15 and to casing 14. By this arrangement it will be seen that the casing may be readily secured in adjusted positions back and forth along the length oi the spring loop. l

l/Vhen the casing is clamped to the loop adjacentthe end ot spring arm 12, which is connected to the diaphragm, a substantially rigid connection is provided between stylus bar 6 and the diaphragm by means ot casing 14, but when the casing is lixed upon the spring loop adjacent its opposite end, as shown in dotted lines in Fig. 2, a relatively resilient connection is formed between the stylus bar and the diaphragm, since the spring arms having the loop now torni a part oithe connection. As a consequence, it will be noted that the vibrations transmitted to the diaphragm from the stylus bar when the casing 14 is secured to the spring loop adjacent its outer end will be slight as compared with the vibrations ttansmitted to the diaphragm when casing 14 is mounted. upon the end of the spring loop which overlies the center of the diaphragm, The intensity ot the tones reproduced will theretore be varied in ac cordance with the adjustment ot casing 111 back and forth along the spring loop, and when the casing 14 is so adjusted as to form relatively slight vibrations the disagreeable scratching` incident to the use of a usual sound reproducer will be eliminated.

The adjustment ot casing 14 thus forms an extremely simple but accurate means for adjusting the intensity ot sounds reproduced to any desired degree.

Various changes may be made without departing from the spirit ot the invention as claimed.

What is claimed is: bar and diaphragm, the ends of said loop 10 1. A sound reprodueer lia-ving a da` connected respectively to said bar and dia-V phra m, a stylus bar, a spring loop projectphragm, a clamp mounted upon said loop ing rom said bar and secured to said diaand arranged for adjustment along the 5 phragm, and a clamp mounted upon said same. Y .Y

spring loop and arranged for adjustment In testimony whereof I have signed my 15 along the same. name toV this Specification.

2. A sound reproducer having a dia-` f t phragm, a stylus bar, a loop connecting said HARRY M. DUNCAN. 

